Obama on Sunday called upon those attending a rally at the baseball stadium in Osceola Heritage Park in central Florida and exhorted the public to "help finish what we (Democrats) started eight years ago."

Obama that all the progress made in the last eight years "goes out the window if we don't win this election. And we win this election if we win Florida", Efe news reported.

With a win in Florida, Clinton could seal her lead over Trump, he said. "So we've got to work our hearts out this week—these next two days—as if our future depends on it," Obama said.

Obama addressed some 11,000 people at the afternoon rally, speaking for about 30 minutes and going over his economic achievements as president, praising Clinton for her work ethic, calling her "the energiser bunny".

Obama won Florida in both 2008 and 2012, but prior to him only Bill Clinton in 1996 had won the state for the Democrats since 1976.

According to official figures on Sunday in Florida, 6.1 million people have voted early or by mail, but only 32,000 more registered Democrats than Republicans have cast ballots, just a 0.5 per cent difference.